:root {
  --Leftlength:50px;
  --toplength:-50px
}
#link-animation {
   position: absolute;
   transition: all 1s;
   top: 0;
   bottom: 0;
   left: 0;
   right: 0;
   z-index: -1;
}

.top {
  top: var(--toplength) !important;
}
.left {
  left: var(--Leftlength) !important;
}
.bottom {
  top: var(--toplength) !important;
}
.right {
  left: var(--Leftlength) !important;
}